System and method for forming barbs on a suture

ABSTRACT

A station for cutting a barb suture is provided. The barb cutting station includes a suture transport assembly for supporting a first suture, a first knife assembly for forming barbs on the first suture, and a first clamp and position assembly for approximating the at least first suture towards the at least first knife assembly. The barb cutting station may further include at least a first suture cutting mechanism configured for severing the at least first suture when a defect is detected. The station may also include at least a first visual inspection assembly configured for detecting defective barbs.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.14/603,487 filed Jan. 23, 2015, which is a continuation of U.S. patentapplication Ser. No. 13/847,207 filed Mar. 19, 2013, now U.S. Pat. No.8,966,728, which is a continuation of U.S. patent application Ser. No.12/726,871 filed Mar. 18, 2010, now U.S. Pat. No. 8,402,621, whichclaims benefit of U.S. Provisional Application No. 61/173,723 filed Apr.29, 2009, and the disclosures of each of the above-identifiedapplications are hereby incorporated by reference in their entirety.

BACKGROUND

Technical Field

The present disclosure relates to medical sutures having barbs formedthereon. More particularly, the present disclosure relates to a systemand method of forming barbs on sutures.

Background of Related Art

Barbed sutures are generally made of the same materials as conventionalsutures and offer several advantages for closing wounds compared withconventional sutures. A barbed suture includes an elongated body thathas one or more spaced barbs, that project from the surface of thesuture body along the body length. The barbs are arranged to allowpassage of the barbed suture in one direction through tissue but resistmovement of the barbed suture in the opposite direction. Thus, oneadvantage of barbed sutures has been the provision of a non-slipattribute.

Barbed sutures are known for use in cosmetic, laparoscopic andendoscopic procedures. The number of barbs called for on a particularsuture may be influenced by the size of the wound and the strengthrequired to hold the wound closed. Like a conventional suture, a barbedsuture may be inserted into tissue using a surgical needle.

In some circumstances, a random configuration of barbs on the exteriorsurface of the suture is preferred to achieve optimal wound closureholding for the particular wound. However, in other circumstances, wherethe wound or tissue repair needed is relatively small, a reduced numberof barbs may be desired. In other circumstances, a two-way barbed sutureis desirable where the barbs permit passing of the suture in onedirection over a portion of the suture and barbs permitting passing ofthe suture in a second direction over another portion of the suture toperform a tight closing stitch.

Various methods of forming barbs on sutures have been proposed such asmechanical cutting, laser cutting, injection molding, stamping,extrusion and the like. Such methods may be difficult to achieve thedesired result with respect to getting the arrangement of barbs in aconfiguration needed for the appropriate procedure and for doing so inan efficient cost effective manner. Conventional cutting methods offorming barbs have significant drawbacks in their ability to maintainsharpness, move rapidly and have slow manufacturing cycle time.

Accordingly, there is a continuing need for a system and method offorming barbs on a suture that is less difficult, more effective andeconomical.

SUMMARY

A station for cutting a barb suture is provided. The barb cuttingstation includes a suture transport assembly for supporting a firstsuture, a first knife assembly for forming barbs on the first suture,and a first clamp and position assembly for approximating the firstsuture towards the first knife assembly. The barb cutting station mayfurther include a first suture cutting mechanism configured for severingthe at least first suture when a defect is detected. The station mayalso include a first visual inspection assembly configured for detectingdefective barbs.

The suture transport assembly, the first knife assembly and the firstclamp and positioning assembly may be mounted to a base panel. The basepanel may be mounted within a cabinet. The first knife assembly mayinclude an ultrasonic mechanism for ultrasonically vibrating a bladeextending therefrom. The first clamp and position assembly includes agripping assembly for selectively gripping the first suture. The suturetransport assembly may include an adjustment mechanism. The suturetransport assembly may include a first pair of rotary motors configuredto rotate the first suture along its longitudinal axis. The suturetransport assembly may include a first tensioning cylinder configured toprovide tension to the first suture.

Also provided is a method of forming a first barbed suture. The methodincludes providing a suture forming station including a suture transportassembly, a first knife assembly, and a first clamp and positionassembly. The method further includes positioning a suture on the suturetransport assembly, aligning the suture transport assembly with theknife assembly, activating the first knife assembly, advancing thesuture transport assembly while simultaneously approximating the firstclamp and position assembly towards the first knife assembly to engagethe suture with the first knife assembly to form a barb, and retractingthe first clamp and position assembly away from the first knifeassembly. Retraction of the first clamp and position assembly may causethe deflection of the barb away from a longitudinal axis of the suture.

The barb forming method may further include the step of advancing thesuture transport assembly relative to the first knife assembly toprepare the suture for a subsequent engagement with the knife assembly.The method may also include the steps of advancing the suture transportassembly and approximating the first clamp and position assembly towardsand away from the knife assembly, one or more times to form additionalbarbs on the suture. The suture transport assembly of the barb formingmethod may be configured to receive a pair of sutures.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present disclosure will be described hereinbelow with reference to the figures wherein:

FIG. 1 is a side view of a barbed suture formed in accordance with thepresent disclosure;

FIG. 2 is a perspective view of a cabinet of a barb cutting stationaccording to an embodiment of the present disclosure;

FIG. 3 is a schematic view of a base panel of the barb cutting stationof FIG. 2;

FIG. 4 is a perspective view of a suture support assembly of the barbcutting station of FIG. 2;

FIG. 5 a schematic view of a pair of clamp and position assemblies ofthe barb cutting station of FIG. 2 showing their respective locations onthe base panel;

FIG. 6 is a perspective view of the clamp and position assembly of FIG.5;

FIG. 7 is a perspective view of a knife assembly of the barb cuttingstation of FIGS. 2; and

FIG. 8 is a side sectional view of a barbed portion of the barbed sutureof FIG. 1.

DETAILED DESCRIPTION

A system and method for forming a barbed suture is herein described.Referring initially to FIG. 1, a barbed suture formed in accordance withthe method of the present disclosure is shown generally as barbed suture10. Suture 10 is formed from a monofilament thread 11, however, it isenvisioned that suture 10 may be formed braided threads, multifilamentthreads and other surgical fibers. Although shown having a circularcross-sectional geometry, the cross-sectional geometry of thread 11 maybe of any suitable shape. For example, thread 11 may be round,elliptical, square, flat, octagonal, and rectangular. Thread 11 may beformed of degradable materials, non-degradable materials, andcombinations thereof. Thread 11 may be formed using any technique withinthe purview of those skilled in the art, such as, for example,extrusion, molding and/or solvent casting.

Still referring to FIG. 1, barbed suture 10 includes a loop 12 formed ona distal end 10 b thereof. Loop 12 is configured to facilitateattachment of distal end 10 b of thread 11 with barb cutting station 100(FIG. 2). Loop 12 may be formed in any manner and may be of any size andconfiguration. It is envisioned that barb cutting station 100 may bemodified such that thread 11 may be attached thereto without loop 12.Optionally, barbed suture 10 includes a suture needle 14 attached to aproximal end 10 a thereof. Needle 14 may be attached to thread 11 priorto or upon completion of the barb forming process. Formed on thread 11between loop 12 and suture needle 14 are a plurality of radially spacedbarbs 16. As will be discussed in greater detail below, barbs 16 mayformed in any number, size, configuration, spacing and/or orientation.

With reference now to FIGS. 2-7, a system for forming barbed suture 10will be described and is shown generally as barb cutting station 100.Referring initially to FIG. 2, barb cutting station 100 includes acabinet 102 having a first housing 104, a second housing 106, and acontrol box 108. First housing 104 is configured to receive a base panel110. Electric components (not shown) are maintained within secondhousing 106. Control box 108 is configured for controlling operation ofcutting station 100. Although shown as a single unit, it is envisionedthat first and second housings 104, 106 and/or control box 108 mayarranged independent of one another. In this manner, cutting station 100may be operated remotely.

Turning now to FIG. 3, maintained within cabinet 102 (FIG. 2) andmounted on base panel 110 are a suture transport assembly 200, a pair ofknife assemblies 300, and a pair of clamp and position assemblies 400.Optionally, mounted to base panel 110 are a pair of suture cuttingmechanisms 600 and/or a pair of visual inspection assemblies 500.

With reference still to FIG. 3, suture transport assembly 200 is mountedto base panel 110 in an upright position along a track 112. Suturetransport assembly 200 is configured to support a pair of sutures 10during the barb forming process. Suture transport assembly 200 isconfigured to move linearly along track 112 perpendicular to knifeassemblies 300, in the direction of arrows “A”.

Turning now to FIG. 4, suture transport assembly 200 includes a basemember 202, a fixed upper support member 204 and an adjustable lowersupport member 206. Fixed upper support member 204 includes a pair ofrotary assemblies 210 each including a pin assembly 212 extendingtherefrom for engaging loops 12 formed on distal ends 10 b of respectivesutures 10. As discussed above, in an alternative embodiment, supportmember 204 are configured to engage sutures 10 without the use of loops12. In this manner, each of support members 204 may include a clamp oranchor (not shown) for attachment of distal ends 10 b of sutures 10thereto.

Still referring to FIG. 4, adjustable lower support member 206 includesa pair of rotary assemblies 220 each including a needle holding assembly222 extending therefrom for engaging proximal ends 10 a (FIG. 1) ofrespective sutures 10. Holding assemblies 222 may include a clamp,anchor or other fixation device suitable for attachment with proximalends 10 of sutures 10. Rotary assemblies 220 each further include atensioning device 223 for tensioning sutures 10 once sutures 10 havebeen received between respective pin assemblies 212 and needle holdingassemblies 222. Tensioning device 223 may be hydraulic, pneumatic,gravity operated, spring-load or otherwise configured to provide tensionto sutures 10. Lower support member 206 further includes an adjustmentmechanism 225 for adjusting the distance between lower support member206 and upper support member 204. In this manner, suture transportassembly 200 may accommodate sutures 10 of various lengths. Each ofupper and lower support members 204, 206 further includes a rotary motor224, 226, respectively, operably connected to rotary assemblies 210,220, respectively, for rotating sutures 10 along longitudinal axisthereof, in the direction of arrows “B”.

Referring briefly back to FIG. 3, knife assemblies 300 are fixedlymounted to base panel 110 adjacent suture transport assembly 200. Knifeassemblies 300 are configured for cutting barbs 16 (FIG. 1) in sutures10. Turning now to FIG. 5, each of knife assemblies 300 includes a base302 and a cutting assembly 304 operably mounted to base 302. Each ofcutting assemblies 304 include a cutting member 306 extending outwardlytherefrom and include a blade 308 for cutting barbs in sutures 10. Asshown, knife assemblies 300 include an ultrasonic mechanism 312 forultrasonically vibrating blade 308. Alternatively, knife assemblies 300may include a heating element or other suitable mechanism (not shown)for heating blade 308. By vibrating or heating blade 308, the forcenecessary to cut barbs 16 may be reduced.

Still referring to FIG. 3, each of cutting assemblies 304 furtherincludes a rotary mechanism 310 for rotating cutting members 306. Rotarymechanism 310 is configured to index blade 308 during the barb formingprocess to adjust the angle of cut. Blade 308 may further be rotated atleast one-hundred and eighty degrees (180°) such that each surface ofblade 308 may be used. In one embodiment, rotation of blade 308 occursonly after the desired number of barbs 16 have been formed along thedesired length of sutures 10. Cutting assemblies 304 are mounted tobases 302 such that cutting members 306 may be advanced, in thedirection of arrows “C”. In this manner, cutting assemblies 222 may beretracted once the barb forming process is completed to permit reloadingand repositioning of suture transport assembly 200. Cutting assemblies304 remain stationary or in a fixed position during the cutting ofsutures 10 to form barbs 16. In this manner, blades 308 are not movedinto contact with the suture, instead clamp and position assemblies 400move suture 10 into contact with blades 308.

Turning to FIGS. 3 and 6, clamp and position assemblies 400 are securelymounted to base panel 110 adjacent suture transport assembly 200 andrespective ultrasonic knife assemblies 300. Clamp and positionassemblies 400 are configured for approximating sutures 10 towards andaway from ultrasonic knife assembly 300. Turning now to FIG. 6, each ofclamp and position assemblies 400 includes a stationary base 402 and amoveable carriage 404. Carriage 404 includes a gripper assembly 406 forselectively gripping suture 10 during the barb forming process. Gripperassembly 406 includes an anvil portion 408 for supporting suture 10 ascarriage 404 is approximated towards cutting member 306 of knifeassembly 300 and as suture 10 engages blade 308.

With reference back to FIG. 3, visual inspection assemblies 500 areconfigured for monitoring the cutting of barbs 16. In the event that amisformed or defective barb is cut, visual inspection assembly 500 isconfigured to signal cutting mechanism 600 to sever the defectivesuture, such that that suture may not be used.

With reference still to FIG. 3, cutting mechanism 600 is configured forcutting suture 10 in the event that a defective barb is detected byvisual inspection assembly 500. Cutting mechanism 600 may further beconfigured for manual actuation by an operator. Cutting mechanism 600may include any device capable of selectively severing suture 10 duringthe barb forming process. Cutting mechanism 600 may include a blade 602,or a laser, a heating element or other suitable device (not shown).

The operation of the suture cutting station 100 will now be describedwith reference to FIGS. 2-7. Initially, cabinet 102 is opened to accessbase panel 110. Suture transport assembly 200 is then adjusted usingadjustment mechanism 225 to configure upper and lower support members204, 206 to accommodate sutures 10 of a given length. Sutures 10 arenext secured to suture transport assembly 200 by hooking loops 12 formedon distal ends 10 b of sutures 10 about pin assemblies 212 of fixedupper support member 204 and fastening armed proximal ends 10 a ofsutures 10 within needle holding assemblies 222 of lower support member206. Tensioning cylinders 223 within rotary assemblies 220 ensure thatsutures 10 are properly tensioned between pin and needle holdingassemblies 212, 222, respectively. Suture transport assembly 200 is thenpositioned such that blades 308 of cutting member 306 are aligned nearproximal ends 10 a of sutures 10.

Once suture transport assembly 200 is properly positioned with respectto ultrasonic knife assemblies 300, cutting assemblies 304 of knifeassemblies 300 are advanced in the direction of arrows “C” (FIG. 3),such that blades 308 of cutting assemblies 306 are positioned outwardsof and in close approximation to (but not in contact with) sutures 10.Knife assemblies 300 are then activated to cause the ultrasonicvibrating or heating of blades 308. Once knife assemblies 300 have beenactivated, cutting assembly 304 remains stationary during the barbforming process and suture transport assembly 200 and clamp and positionassemblies 400 operate in unison to move sutures 10 relative to blade308 to form barbs 16 (FIG. 1) along the lengths thereof

With reference to FIG. 8, barbs 16 are formed in two steps. A firstportion 22 of the cut is made at an angle (“β”) of from about thirty toabout forty degrees (30°-40°) with respect to the surface of the sutureto a predetermined depth. In this manner, clamp and position assemblies400 are approximated towards blades 308 (arrow “D”) while suturetransport assembly 200 advances sutures 10 longitudinally (arrow “A”).The angle of cut is then adjusted for the second portion 24 to an angle(“α”) of from about two to about eight degrees (2°-10°) with respect tothe surface or longitudinal axis of suture 10 by varying the rate ofmovement of clamp and position assemblies 400 and suture transportassembly 200 relative to each other and blade 308.

Upon completion of the second cut, clamp and position assemblies 400 areapproximated away from cutting assemblies 304 thereby causing blades 308to engage, and thus, flex barbs 16 outwardly. Sutures 10 are thenreleased from gripper assemblies 406 as clamp and position assemblies400 continue to move away from cutting assemblies 304 to permit suture10 to be repositioned for the next cut. Suture transport assembly 200then advances sutures 10 relative to cutting assemblies 306 as rotaryassemblies 210, 220 rotate sutures 10 along longitudinal axis thereof toready sutures 10 for the next cut. Depending on the desiredconfiguration of barbs 16 along a length thereof, rotary assemblies 210,220 may be configured to rotate sutures 10 from zero degrees (0°) thruthree-hundred sixty degrees (360°) along a length thereof.

Additional barbs 16 are formed in the manner described above. Thisprocess continues until barbs 20 are formed along the desired lengths ofsutures 10. Knife assemblies 300 are then retracted to permit suturetransport assembly 200 to return to an initial position. Sutures 10 arethen unloaded and the barb forming process is complete.

During barb formation, visual inspection assemblies 500 (FIG. 3) monitorthe characteristics of barbs 16. In the event a barb is detected thatdoes not conform to the desired configuration, suture cutting mechanism600 (FIG. 3) is activated, thereby severing suture 10 and terminatingthe barb forming process.

Barb cutting station 100 may be configured to cut barbs 16 in anysuitable pattern, for example, helical, linear, or randomly spaced. Thepattern may be symmetrical or asymmetrical. The number, configuration,spacing and surface area of the barbs may vary depending upon the tissuein which barbed suture 10 is used, as well as the composition andgeometry of the material utilized to form suture 10. Additionally, theproportions of barbs 16 may remain relatively constant while the overalllength and spacing thereof may be determined by the tissue beingconnected. For example, if barbed suture 10 is to be used to connect theedges of a wound in skin or tendon, barbs 16 may be made relativelyshort and more rigid to facilitate entry into this rather firm tissue.Alternatively, if barbed suture 10 is intended for use in fatty tissue,which is relatively soft, barbs 16 may be made longer and spaced furtherapart to increase the ability of the suture to grip the soft tissue.

The surface area of barbs 16 may also vary. For example, fuller-tippedbarbs may be made of varying sizes designed for specific surgicalapplications. For joining fat and relatively soft tissues, larger barbsmay be desired, whereas smaller barbs may be more suitable forcollagen-dense tissues. In some embodiments, a combination of large andsmall barbs within the same structure may be beneficial, for examplewhen a suture is used in tissue repair with differing layer structures.Use of the combination of large and small barbs with the same suturewherein barb sizes are customized for each tissue layer will ensuremaximum anchoring properties. In particular embodiments, a singledirectional suture may have both large and small barbs; in otherembodiments a bi-directional suture may have both large and small barbs.The barbs formed may include geometrical shapes such as round,triangular, square, oblique, elliptical, octagonal, rectangular, andflat

While the above description contains many specifics, these specificsshould not be construed as limitations on the scope of the disclosure,but merely as exemplifications of embodiments thereof. Those skilled inthe art will envision many other possibilities within the scope andspirit of the disclosure as defined by the claims appended hereto.

1. A method of forming barbs on a suture comprising: securing first andsecond ends of a suture to a suture transport; positioning the suturerelative to a knife assembly including a knife; clamping the suture;moving the suture into engagement with the knife; and moving the sutureout of engagement with the knife.
 2. The method of claim 1, whereinsecuring the first and second ends of the suture to the suture transportincludes hooking a loop of the suture about a pin assembly of the suturetransport, and fastening a needle of the suture to a needle holdingassembly of the suture transport.
 3. The method of claim 1, whereinpositioning the suture relative to the knife assembly includes advancingthe suture transport.
 4. The method of claim 1, further includingadjusting the suture transport to accommodate the suture.
 5. The methodof claim 1, further including moving the suture while the suture is inengagement with the knife.
 6. The method of claim 5, wherein moving thesuture while the suture is in engagement with the knife includesadvancing the suture.
 7. The method of claim 5, wherein moving thesuture while the suture is in engagement with the knife includes movingthe suture laterally.
 8. The method of claim 1, further includingdetecting a defect in the suture.
 9. The method of claim 8, furtherincluding cutting the suture after the defect in the suture is detected.10. The method of claim 1, further including activating an ultrasonicmechanism for ultrasonically vibrating the knife.
 11. The method ofclaim 1, further including activating a heating element to heat theknife.
 12. The method of claim 1, further including advancing the suturesubsequent to moving the suture out of engagement with the knife. 13.The method of claim 12, wherein in advancing the suture subsequent tomoving the suture out of engagement with the knife includes rotating thesuture about a longitudinal axis of the suture.
 14. The method of claim1, wherein clamping the suture includes engaging the suture with aclamping and positioning assembly.
 15. The method of claim 14, whereinmoving the suture into engagement with the knife is performed by theclamping and positioning assembly.
 16. A barbed suture formed using themethod of claim 1.